1. Field of Invention
The present invention relates to a tablet for transmucosal administration of a medicament. Specifically, it relates to a tablet that will give a rapid release of nicotine.
2. Description of Prior Art
Nicotine is the most widely distributed of the plant alkaloids. It occurs in two separate phyla of the plant kingdom, Pteridophytes and Spermatophytes. Despite its wide distribution, for practical purposes, nicotine is obtained from the tabacum and rustica species of the Nicotina genus. However, it is interesting that Australian Aboriginal people chewed "pituri", a nicotine preparation made from Duboisia hopoodi.
Nicotine can be isolated as an oily, volatile base with a sharp burning taste. Nicotine will form acid salts with most acids. Nicotine can be introduced into the body in many ways. The most popular way is by smoking cigarettes. When a cigarette is smoked, the partial oxidation of the tobacco causes the vaporizing of some of the nicotine. The nicotine vapor as well as nicotine adsorbed on partial oxidation products of the cigarette is quickly absorbed through the lungs. A dozen beats of the heart can carry nicotine from the lungs to the brain in less than 20 seconds.
Smoking cigarettes introduces many undesirable materials into the person smoking, as well as into the environment. Because of this, most smokers would like to quit smoking. However, a craving for nicotine, irritability, restlessness, difficulty in concentrating, headaches, an increase in weight, and anxiety often follow cessation of smoking. Supplying nicotine in an alternative way has been helpful in some cases of those wishing to quit smoking. Several alternative ways of delivering nicotine have been proposed.
Pomerleau (Psychopharmacology 1992, 108, 519-526) listed some of the criteria that should be met for an alternative nicotine dosing method to be considered satisfactory: 1) the method should be safe and easy to use; 2) specified doses should be accurately and reproducibly delivered; and 3) the pharmacokinetics should resemble those of cigarette smoking. The following is a review of the major alternative nicotine dosing methods and their drawbacks, i.e., how they fail or meet these criteria.
Frith (Life Sciences, 1967, 6, 321-326) described experiments where tablets containing 0.1 mg of nicotine were administered orally. The subjects were instructed to chew the tablets until the tablets were dissolved. These tablets had the nicotine distributed uniformly throughout the tablets. The pharmacokinetics did not resemble those of cigarette smoking.
Lennox M. Johnston and M. D. Glasg in the Dec. 19, 1942 edition of Lancet, p.742, described intravenous injection of nicotine. They reported that after several injections, an injection was preferred to a cigarette. Intravenous injection has continued to be used in scientific experimentation. See for example Lucchesi et al. (Clin. Pharm. Ther., 1967, 8, 789-96), Soria et al. (Psychopharmacology 1996, 128, 1000-1005), Benowitz et al. (J. of Pharmacol. Exp. Ther. 1990, 254, 1000-1005), and Rosenberg et al. (Clin. Pharmacol. Exp. Ther. 1980, 28, 516-22). However, intravenous injection is obviously not a suitable replacement for smoking in most situations.
Jarvik et al. (Clin. Pharm. Ther. 1970,11, 574-576) described experiments where 10 mg tablets of nicotine tartrate were swallowed at two hour intervals by several subjects. The idea was that although the ionic form of nicotine would not be absorbed in the stomach, it would be absorbed in the intestine. However, most of the nicotine absorbed in the intestine is metabolized by the liver before it reaches the nervous system. The large amounts of nicotine in these experiments, as compared with about 1 mg available in a cigarette, had only a small effect. (Actually the abstract of this paper states that 10 mg of nicotine tartrate per kilogram was administered, but this is an obvious error.) The pharmacokinetics of swallowed nicotine did not resemble smoking.
Wesnes and Warburton (Psychopharmacology, 1984, 82, 147-150) described experiments where nicotine was added to dextrose tablets. They also (Psychopharmacology, 1986, 89, 55-59) used nicotine absorbed in magnesium hydroxide pills. In their experiments they covered the taste of nicotine with hot pepper sauce. The sauce is acidic. Travel (Ann. New York Ac. Sc., 1960, 80, 13-32) had found that nicotine is more readily absorbed in its base form rather than as its acid salts. Beckett et al. (J. of Pharmacy and Pharmacology, 1971, 24, 115-120) had found that solutions of nicotine were more rapidly absorbed in the buccal cavity if they had an alkaline pH. Under the conditions of the experiments by Wesnes and Warburton, the alkaline reaction of the basic magnesium hydroxide would be useful. In the experiments of Wesnes and Warbuton a dilute nicotine solution was allowed to soak into the dextrose or magnesium hydroxide pills. The subjects were requested to hold the pills in their mouths for 5 minutes before swallowing. The described pills did not give a rapid release of nicotine.
Shaw (U.S. Pat. No. 4,806,356, 1989) described a lozenge made by compression molding with nicotine distributed uniformly throughout. Shaw's lozenges will slowly release nicotine. Santus (U.S. Pat. No. 5,549,906, 1996) described nicotine-containing lozenges where the nicotine is uniformly distributed through a nonnutritive sweetener and an absorbent excipient. Santus discussed how the administration of nicotine is obtained by allowing the lozenge to completely dissolve in the mouth. Several nicotine lozenges have been commercialized and are available as over-the-counter products in the U.K. These contain 0.5 mg nicotine distributed uniformly throughout the lozenges. The pharmacokinetics of these methods of dosing is not like smoking.
Sahakian et al. (Brit. J. Psychiatry, 1989,154, 797-800) described using a subcutaneous injection of nicotine. While of possible use in scientific studies, this does not fill the need for the usual smoker. Under some conditions, such an injection can cause severe muscular irritation.
The absorption of drugs such as nitroglycerin and scopolamine through the skin is a common occurrence. The absorption of nicotine through the skin has also long been known. Workers coming into physical contact with dew on tobacco leaves can develop what is called "green tobacco sickness". See for example Gehlbach et al. (J.A.M.A., 1974, 229, 1880-1883). The transdermal administration of nicotine has been the subject of many patents. For example, Baker et al. U.S. Pat. No. 4,839,174, 1989, U.S. Pat. No. 4,943,435, 1990, and U.S. Pat. No. 5,135,753, 1992. The commercial products based on these patents have turned out to be quite expensive. More importantly, the patches give a rather constant level of nicotine in the blood. Transdermal nicotine patches have another disadvantage in that it is difficult to administer nicotine at the rate required by different subjects. Benowitz et al. (J. Pharmacol. Exp. Ther., 1982, 21, 368-373) and Feyerabend et al. (Brit. J. Clin. Pharmacol. 1985, 19, 239-249) have found that there are up to four-fold variations in the rate nicotine is eliminated by smokers. It is also advantageous for users to be able to vary dosage to cope with times of intense craving.
Nicotine chewing gum is another way of administering nicotine. Ellis et al. (U.S. Pat. No. 865,026, 1907) provides an early example. More recent examples are Ferno et al. (U.S. Pat. No. 3,845,217, 1974) and Lichtneckert et al. (U.S. Pat. No. 3,877,468, 1975 and U.S. Pat. No. 3,901,248, 1975). Products of these patents are now being marketed on an international scale. These products combine a nicotine-containing cation exchange resin complex in a gum base. However, chewing gum is not socially acceptable in some circumstances. Some users of nicotine gum have complained about the effort required to chew it. Many users complain about the taste. The pharmacokinetics are different than smoking.
Much has been learned in recent years. Russell (Nicotine Replacement: A Critical Evaluation: Pomerleau, O. F. and Pomerleau, C. S., eds.; Alan R. Liss, Inc.: New York 1988, 63-94) observed that cigarette smoking provides an initial sharp rise in blood nicotine level which is missing in transdermal nicotine and in nicotine gum. Henningfield et al. (Drug Alcohol Dependence, 1993, 33, 23-39) showed that the arteriovenous differences during cigarette smoking are substantial, with arterial levels exceeding venous levels six- to ten-fold. Benowitz (Nicotine Safety and Toxicity, Benowitz, Neal L., ed.; Oxford: New York 1998, 3-16) observed that there is an intense pharmacological response due to the high levels of nicotine entering the brain and the effects occurring rapidly before the development of tolerance. The nicotine level in the brain declines between cigarettes as the nicotine is distributed to other body tissues. This decline in nicotine level provides an opportunity for resensitization of receptors, allowing some positive reinforcement despite the development of tolerance.
These conclusions have been verified by Stitzer and DeWit (Nicotine Safety and Toxicity, Benowitz, Neal L., ed.; Oxford: New York 1998, 119-131) where they measured the acceptance by cigarette smokers of an intravenous injection, a nasal spray, a vapor inhaler, nicotine gum, and a nicotine patch. A rating scale was used where the subjects gave 0 for liking "not at all" and 4 for liking "awful lot". Both the 2 and 4 mg. nicotine gums were given negative ratings. The nasal spray, the vapor inhaler and the nicotine patch all were given ratings of about 0. The average rating by the subjects for an injection of 1.5 mg of nicotine was 0.8 and for 3 mg the rating was 2.6. The average ratings for 1.4 mg cigarettes was 1.5 and for 2.9 mg cigarettes was 1.8. The high rating of the intravenous injection shows that a rapid increase in venous levels can give brain nicotine levels that give satisfaction to the smoker. However, nicotine administration by means that did not give a rapid increase in nicotine level was not found acceptable.
There have been several proposals to overcome the failure of transdermal patches and nicotine gum to deliver the sharp peak in blood nicotine level that is necessary to satisfy many smokers. For example, Rose et al. (U.S. Pat. No. 5,834,011, 1998) suggested using a nasal spray to give a rapid administration of nicotine. Rose suggested further that the aerosol be combined with transdermal patches. The aerosol delivery system is inconvenient and unpleasant for the user, as well as being expensive.
Baker et al. (U.S. Pat. No. 5,135,753, 1992) suggested combining transdermal patches with buccal administration of nicotine. The suggested tablets have their nicotine distributed uniformly and will not give the rapid release of nicotine that is lacking in the transdermal patches.
Perfetti (U.S. Pat. No. 5,488,962, 1996) has addressed some of the problems with the present nicotine gum. Perfetti proposed elimination of the cation-exchange resin and to use lower levels of nicotine in the gum. The improved gum described by Perfetti is still not convenient for the user. The improved gum will still not give the sharp nicotine peak that is desired.
Russell et al. (Brit. Med. J, 1983, 286, 683-684) described a nasal solution that could deliver nicotine via the nose. A two-percent solution of nicotine was combined with a thickening agent. Each dose was contained in a plastic container that could be opened and squeezed to administer the nicotine. These doses have the disadvantage of being expensive to manufacture and inconvenient to use. Ferno et al. was granted U.S. Pat. No. 4,579,588, 1986 for a similar idea.
Ray et al. (U.S. Pat. No. 4,655,231, 1987) described a synthetic snuff, which consists of a powdered salt of nicotine diluted with powdered organic sugars. Snuff is inconvenient for the user and is not socially acceptable.
Pomerleau et al. (Psychopharmacology, 1992, 108, 518-526) described an intranasal aerosol delivering system. This is an excellent method of delivering nicotine in a laboratory. It is capable of giving the short, intense pulses of nicotine that are desired. However, it is inconvenient for the user and not practical in most applications outside the laboratory.
Misra et al. (U.S. Pat. No. 5,869,098, 1999) described a device for making comestible units. These units might contain nicotine. The nicotine would be distributed uniformly through the units. The process for making these units is complicated and expensive.
Ray (U.S. Pat. No. 4,284,089, 1981) described the use of a device to vaporize nicotine. Unfortunately, nicotine vapor has a bad taste and the described device does not provide sufficient nicotine to satisfy cigarette smokers. This device is not convenient for the user and is expensive.
Volsey, II (U.S. Pat. No. 5,865,186, 1999) described a heated device that might overcome the problem that the Ray's device had in terms of the quantity of nicotine available. This device is not convenient for the user and is complicated.
Keith and Snipes (U.S. Pat. No. 4,764,378, 1988) described a buccal dosage form for transmucosal administration of nicotine. Their device attaches itself within the mouth and delivers the drug over several minutes. This device has the same disadvantages as nicotine gum.
Knudsen and Rasmussen (U.S. Pat. No. 5,284,163, 1994) described a device for administering a powdered or granular material containing nicotine into the oral cavity. The nicotine containing material is chewed together with gum. Their device has the same disadvantages as the nicotine gum.
Ray and Ellis patented an oral nicotine dispenser. Their U.S. Pat. No. 4,907,605, 1990, is specifically designed to slowly release nicotine. The nicotine is sorbed into polymeric materials. Ray and Ellis described the release of thirty percent of the nicotine per hour.
Rose et al. (U.S. Pat. No. 4,953,572, 1990) described the use of an aerosol to deliver nicotine to the oral cavity of an individual. As stated, this is an effective way of supplying nicotine to be absorbed rapidly. However, it is complicated, unpleasant for the user, and expensive.
Mondre received U.S. Pat. No. 5,035,252 in 1990. The Mondre patent covers using a dental floss containing nicotine. While it is quite likely that nicotine will be absorbed from nicotine containing dental floss, it is unlikely that cigarette smokers would be willing to floss as often as they would smoke a cigarette.
Mascarelli patented a lollypop that contained nicotine. His U.S. Pat. No. 5,048,544, 1991, is based on the assumption that smokers would accept lollypops as socially acceptable. To actually function, the lollypop would need to be placed in the mouth for a short time. Then must the wet, sticky lollypop be removed from the mouth for minutes, or even hours. In the event a lower concentration of nicotine is employed, the lollypop can left in the mouth but would not give the initial high dose of nicotine that has been shown to be required.
Place et al. (U.S. Pat. No. 5,147,654, 1992) described a complicated osmotic device for delivering nicotine. The device basically delivers nicotine at a constant rate over an extended time period.
Chase (U.S. Pat. No. 5,666,979, 1997, U.S. Pat. No. 5,875,786) described a cigar like carrier for nicotine. When the end of this device is chewed, the nicotine containing material is slowly released in the mouth. The nicotine is absorbed through the buccal mucous. This is complicated to manufacture and inconvenient to use.
Monte (U.S. Pat. No. 5,810,018, 1998) described a complicated procedure involving sprays containing nicotine, a sequestering agent and one or more stimulants. This procedure is difficult to implement and is expensive.
Olovson (U.S. Pat. No. 5,645,088, 1997) described a device adapted to be held between the frontal teeth and the inner surface of the lips. The peripheral part of the holder is made of a saliva-dissolvable material, which in some cases contains nicotine. This is a complicated way of getting nicotine to be absorbed in the mouth.
Dam (U.S. Pat. No. 5,525,351,1996 and U.S. Pat. No. 5,733,574, 1998) described a nicotine-containing gel. These units are designed to have a disintegration time of 5-60 minutes. During this time, they release nicotine at a relatively constant rate.
Monte (U.S. Pat. No. 5,810,018, 1998) described the use of a sequestering agent to facilitate the absorption of nicotine in the mouth when a nicotine containing solution is sprayed into the oral cavity. This procedure is inconvenient for the user and costly to manufacture.
Stanley and Haque were granted U.S. Pat. No. 5,824,334 on Oct. 20, 1998. They described a holder and a nicotine-containing tablet. Stanley's system requires the user to place the holder in his mouth like a cigarette holder whereupon the saliva dissolves the nicotine-containing tablet. Their procedure is more complicated than has been found necessary or desired. They obtain their short pulses of nicotine by physically removing the tablets from the subject's mouth. Their earlier U.S. Pat. No. 4,571,953, 1987 for a nicotine-containing lollipop is again for a removable nicotine source. It is similar to Mascarelli's device, supra.